Joint space in normal gleno-humeral radiographs.

The gleno-humeral joint space in standard antero-posterior images of 175 normal subjects was measured at three different sites. The average of the three measurements, the integral joint space, was calculated and was found to be between 4 and 5 mm. The value does not change with age, except in women, in whom it increases slightly. A narrow joint space in an elderly patient should not be expected simply because the patient is old. The measuring technique described is useful in population studies. In individual cases a simple measurement with a ruler serves the same purpose.